法莫替丁壳聚糖缓释微囊的制备工艺研究

制备了法莫替丁壳聚糖微囊,探讨了各种因素对微囊质量的影响关系,确定了制备微囊的最佳工艺。     

对乙酰氨基酚复合微囊缓释栓的制备及体外释放度研究

目的:采用复凝聚法制备对乙酰氨基酚(AAP)微囊并考察其体外释药行为。制备AAP复合微囊栓剂,具有良好释放效果。方法:考察复凝聚法制备AAP微囊过程的处方和工艺因素,并进行正交试验设计,筛选出最佳条件制备AAP微囊并考察其体外释药行为。同时采用复合缓释技术(速释部分+微囊缓释)制备复合微囊缓释栓剂,考察其释药行为。结果:建立了复凝聚法制备AAP微囊方法,优化后的制备条件为:明胶阿拉伯胶囊材用量各为7 g(溶液浓度7%),药物用量为8 g,搅拌速度为300 r·min^-1,制备温度55℃。此条件制备的微囊形态圆整,粒径均匀,重复性好,包封率为(79.71±0.10)%,载药量为23.11±0.69%。微囊有缓释效果,拟合缓释方程符合一级方程。制备的复合微囊栓与普通栓剂相比,具有更好的释放效果,其中缓释过程药物释放符合Higuchi方程。结论:基于普通栓剂与复合微囊技术制备的新型AAP栓具有更佳的释药特性。     

正交实验设计优化岩白菜素微囊的制备工艺

目的优化岩白菜素微囊的制备工艺,并对制备的岩白菜素微囊进行质量评价。方法以明胶为囊材,单凝聚法制备岩白菜素微囊,通过正交实验设计优化其制备工艺,并对包封率、载药量、平均粒径、体外溶出率进行研究。结果明胶制备岩白菜素微囊的最佳工艺条件为:明胶质量分数为6%,囊心囊材质量比为1∶2,搅拌速度为750r·min^-1。此最佳工艺制备的岩白菜素微囊包封率为75.90%,载药量为23.09%,体外溶出度测定30min为28.6%,12h累计释放达到90%以上。结论以最佳工艺条件制备岩白菜素微囊工艺稳定,包封率高,同时体外释放实验表明,该微囊具有较好的缓释作用。     

番茄红素微囊的制备及稳定性考察

目的:制备番茄红素微囊,并对其稳定性进行考察.方法:用单凝聚法制备微囊,并用正交实验优化制备工艺.用分光光度法测定番茄红素的含量.结果:番茄红素微囊的最佳制备工艺为囊心囊材质量比0.2∶1,温度50℃,转速400r·min-1.在不同的影响因素条件下,微囊的稳定性明显优于原料(P<0.05).结论:番茄红素微囊的制备工艺简单,重现性好,且外观形态良好,微囊化是提高番茄红素稳定性的有效途径.     

复凝聚法制备吲哚美辛缓释微囊的研究

目的:通过吲哚美辛微囊的制备研究,为吲哚美辛的缓释制剂提供科学依据。方法:以微囊的药物包封率为制备工艺优化指标,利用复凝聚法,通过正交实验得出微囊的最佳制备工艺条件。结果:该法所制备微囊的粒度分布在2.2~32.3μm之间,收率可达80%以上。结论:实验证明,吲哚美辛微囊比吲哚美辛片剂具有明显的缓释作用。     

铁叶绿酸钠微囊的制备及释放度测定

目的:制备铁叶绿酸钠微囊,并考察其体外释放情况。方法:采用优化的溶剂挥发法制备铁叶绿酸钠微囊,以正交试验确定制备工艺。结果:铁叶绿酸钠微囊的最佳制备工艺为EC与内相铁叶绿酸钠比为2:1、以1%PVA为分散剂、EC浓度为3%、搅拌速度为700 r·min^-1。结论:铁叶绿酸钠微囊制备方法简单,微囊具有明显的缓释作用。     

左旋多巴微囊制备工艺的研究

目的以乙基纤维素为囊材,优选左旋多巴微囊的制备工艺。方法以微囊的包封率及载药量为评价指标,采用正交实验优选左旋多巴微囊液中干燥法制备工艺条件,并对制备的微囊进行质量检查。结果优选出的制备工艺为:囊材与药量比例为0.6∶1.4,油水相比例为105∶30,PVP量为0.2g,验证实验表明,优化工艺所制左旋多巴微囊的平均载药量为54.94%,平均包封率为89.2%。质量检查结果表明,微囊外观圆整且无粘连现象,大部分微囊的粒径分布在300～600μm范围内。优选出的左旋多巴微囊在体外具有明显的缓释效果。结论采用液中干燥法制备左旋多巴微囊,工艺稳定可靠,操作简便,工艺条件合理、可行。     

恩诺沙星微囊的制备

目的:制备恩诺沙星微囊及工艺优化。方法:本实验采用单凝聚法制备恩诺沙星微囊,应用显微镜观察产品的形态,采用紫外分光光度法测定微囊中恩诺沙星的包封率。结果:恩诺沙星微囊在显微镜下观察为圆球形微囊,紫外分光光度法测得产品包封率为48.15%。结论:单凝聚法可成功制备恩诺沙星微囊,方法简单,包封率较高,可操作性强。     

壳聚糖-阿司匹林缓释微囊的制备工艺及体外溶出实验

以壳聚糖和阿拉伯胶为囊材,探讨将阿司匹林微囊化的制备工艺及缓释测定。以微囊的药物包封率为制备工艺优化指标,利用复凝聚法,通过正交实验得出微囊的最佳制备工艺条件:壳聚糖浓度为0.6%、成囊pH为4.5、搅拌速度为200r.m in-1、成囊温度为60℃为最佳工艺条件。以最佳制备工艺条件制备含药微囊,重现性好,工艺稳定,同时体外溶出实验表明,该微囊具有较好的缓释作用。     

单、复凝聚法制备酮康唑微囊的性状和包封率比较

目的:比较单、复凝聚法制备微囊的外观性状和包封率,为进一步研究微囊的制备工艺打下基础。方法:以酮康唑作为囊芯物,用明胶和阿拉伯胶作囊材,采用常规的单、复凝聚法分别制备酮康唑微囊,并在光学显微镜下比较其外观性状;采用单波长紫外分光光度法建立微囊中酮康唑含量测定方法,在此基础上计算其药物包封率。结果:2种方法所得的微囊均为白色粉末,采用单凝聚法得到的微囊平均粒径为32.20μm, 相对包封率为56.11%;复凝聚法制备的微囊则分别为7.99μm和83.42%。结论:采用相分离-凝聚法制备微囊时,复凝聚法所得结果较好。     

Sustained-release tablets of indomethacin-loaded microcapsules: preparation, in vitro and in vivo characterization

Indomethacin (IDM) was encapsulated in gelatin-cellulose acetate phthalate (CAP) microcapsules (A) by complex coacervation method and in CAP microcapsules (B) by simple coacervation method. Microcapsules A and B, having mean diameters of 38.24 and 35.74 microm, respectively, were used to prepare sustained-release tablets A and B. The activation energy of thermal degradation for tablets A and B was calculated based on differential scanning calorimetry (DSC) to be 258.9 and 284.8 kcal/mol, respectively. In vitro release profiles showed no burst effect and release t(1/2) of the two sustained-release tablets were found to be 41.30+/-1.86 and 33.25+/-2.84 min, respectively, while that of IDM plain tablets C was 6.30+/-0.39 min (P<0.01). In vitro release of IDM from tablets A and B could be described by Higuchi equation and zero-order kinetics, respectively. After per os (po) administration with physiological saline, their irritation to rat stomach was obviously reduced in comparison with tablets C. Pharmacokinetic study in rabbits showed that t(max) was delayed and C(max) lowered compared with tablets C and the values of AUC(0-24 h) of the three tablets were very close.     

吲哚美辛肠溶滴丸的研制及其体外释药研究

研制吲哚关辛（IDM）肠溶滴丸,并考察其体外释药特性。方法：选用PEG6000为基质,用正交试验筛选IDM滴丸的最佳处方及工艺,并采用聚丙烯酸树脂Ⅱ为肠溶材料对其进行包衣,制备IDM肠溶滴丸。转篮法对其体外释药特性进行考察,并与市售IDM肠溶片进行比较。结果：筛选出IDM滴丸最佳制备条件为：IDM与总基质的质量比为1：3,滴速为65滴／min,滴制温度为90℃,冷凝液温度为5℃。IDM肠溶滴丸及市售IDM肠溶片在酸性介质中几乎不释药,而在pH为6.8的磷酸盐缓冲液中,IDM肠溶滴丸的释药速度显著高于市售肠溶片（P〈0．05）。结论：IDM肠溶滴丸具有明显肠溶效果,同时可加快IDM在肠道中的释放速度,值得进一步研究。     

吲哚美辛-PEG 6000滴丸的研究

以聚乙二醇6000(简称PEG 6000)为载体制成吲哚美辛滴丸。测得滴丸的溶解度比原药吲哚美辛增大一倍多,剂量减半时,滴丸对大鼠胃的刺激性显著降低,且仍有抑制基础胃酸分泌的作用。     

Enhanced absorption of indomethacin after oral or rectal administration of a self-emulsifying system containing indomethacin to rats

A self-emulsifying system (SES), a mixture of an oil and a surfactant which forms an oil-in-water emulsion, is expected to improve the in vitro drug dissolution and enhance the in vivo drug absorption. In this study, a poorly water-soluble drug, indomethacin (IDM) was incorporated into the SES to increase bioavailability. The SES with 30% of Tween 85 and 70% of ethyl oleate, EO (w/w) was selected as an optimized formulation (high drug loading, low surfactant concentration, and small particle size). After an oral administration of the SES containing IDM and IDM suspension, (IDM was suspended in methyl cellulose), 22.5 mg/kg as IDM, to rats, the area under the plasma concentration-time curve from time zero to the last measured time in plasma, 12 h (AUC(0-12 h)) was significantly greater (57% increase) in the SES, suggesting that oral absorption of IDM increased significantly by the SES. After a rectal administration of gelatin hollow type suppositories, filled with the SES containing IDM and IDM powder physically mixed with the SES, 22. 5 mg/kg, to rats, the AUC(0-12 h) also increased significantly (41% increase) by the SES, suggesting that rectal absorption of IDM also increased significantly by the SES.     

Assessment of adverse drug reactions in psychiatric hospitals

Summary A system for monitoring adverse drug reactions (ADR) in psychiatric inpatients was introduced in psychiatric hospitals in the FRG in May 1979. It consists of intensive drug monitoring (IDM) and a so-called organized spontaneous reporting system (OSR). ADR are rated separately according to impact on therapy and probability of causal relationship. With IDM all ADR (Grades I–III) are assessed in a randomly selected sample of inpatients. With OSR only ADR leading to discontinuation of the drugs in question (=ADR Grade III) are assessed. In 406 drug-treated inpatients monitored by IDM in the psychiatric hospitals of Berlin and Munich from May 1979 to Dec. 1981, ADR were observed in 60,4%. In 15% of IDM-patients ADR led to discontinuation of the drugs in question; with OSR the relative frequency of these Grade III ADR was 9,0% in 5096 patients monitored throughout the entire period. Life-threatening events were observed in 1,2% of patients undergoing IDM as well as 1.2% of those undergoing OSR. The most frequently observed ADR by IDM were sedation, extrapyramidal signs, disturbances of the autonomic nervous system and increase in transaminases, and by OSR Parkinsonism, akathisia, sedation, toxic delirium and increased transaminases. The relative frequency of Grade III ADR was similar for neuroleptics and antidepressants (5,4% and 5,3% in OSR); a very low relative frequency of ADR Grade III was found for tranquilizers and hypnotics (0,7% and 0,2%). Methodological aspects of this drug monitoring system are discussed in the light of current literature.     

T-type channel blocking properties and antiabsence activity of two imidazo[1,2-b]pyridazine derivatives structurally related to indomethacin

It is presently unclear whether the antiseizure effects exerted by NSAIDs are totally dependent on COX inhibition or not. To clarify this point we investigated whether 7-methyl-2-phenylimidazo[1,2-b]pyridazine-3-carboxylic acid (DM1) and 6-methoxy-2-phenylimidazo[1,2-b]pyridazine-3-carboxylic acid (DM2), two imidazo[1,2-b]pyridazines structurally related to indomethacin (IDM) but ineffective in blocking COXs, retain IDM antiabsence activity. When administered by intraperitoneal injection in WAG/Rij rats, a rat strain which spontaneously develops SWDs, both DM1 and DM2 dose-dependently suppressed the occurrence of these seizures. Importantly, these compounds were both more potent in suppressing SWD occurrence than IDM. As T-type channel blockade is considered a mechanism of action common to many antiabsence drugs we explored by whole cell patch clamp electrophysiology in stably transfected HEK-293 the effect of DM1 and DM2 on Ca_V3.1 channels, the T-type channel subtype preferentially expressed in ventrobasal thalamic nuclei. Both these compounds dose-dependently suppressed the currents elicited by membrane depolarization in these cells. A similar T-type blocking effect was also observed when the cells were exposed to IDM. In conclusion, DM1 and DM2 whilst inactive on COXs, are potent antiabsence drugs. This suggests that compounds with structural features typical of NSAIDs may exert antiepileptic activity independently from COX inhibition and possibly by a direct interaction with T-type voltage-dependent Ca²⁺ channels.     

Influence of Plasticizer Level on the Drug Release from Sustained Release Film Coated and Hot-Melt Extruded Dosage Forms

In the current study, the influence of plasticizer level on drug release was investigated for solid dosage forms prepared by hot-melt extrusion and film coating. The properties of two highly water-soluble compounds, diltiazem hydrochloride (DTZ) and chlorpheniramine maleate (CPM), and a poorly water-soluble drug, indomethacin (IDM), were investigated in the melt extrudates containing either Eudragit® RSPO or Eudragit® RD 100 and triethyl citrate (TEC) as the plasticizer. In addition, pellets containing DTZ were film coated with Eudragit® RS 30D and varying levels of TEC using a fluidized bed coating unit. Differential scanning calorimetry (DSC) demonstrated that both CPM and IDM exhibited a plasticization effect on the acrylic polymers, whereas no plasticizing effect by DTZ on Eudragit® RSPO was observed. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of the DTZ, Eudragit® RSPO and TEC at 140 °C, the maximum temperature used in the hot-melt extrusion process. The chemical stability of DTZ and IDM in the extrudate following hot-melt processing was determined by high pressure liquid chromatography (HPLC). Drug release rates of both DTZ and CPM from hot-melt extrudates increased with an increase in the TEC level in the formulations, while the release rate of DTZ from the Eudragit® RS 30D–coated pellets decreased with an increase in TEC in the coating dispersion. This phenomenon was due to the formation of a reservoir polymeric structure as a result of the thermal stress and shear stress involved in the hot-melt extrusion process regardless of the TEC level. In contrast, coalescence of the polymer particles in the film coating process was enhanced with higher levels of TEC, as demonstrated by scanning electron microscopy (SEM). The addition of TEC (0% to 8%) in the IDM hot-melt extrudate formulation had no influence on the drug release rate as the drug release rate was controlled by drug diffusion through the inside of the polymeric materials rather than between the polymer particles.     

Mifamurtide: CGP 19835, CGP 19835A, L-MTP-PE, liposomal MTP-PE, MLV 19835A, MTP-PE, muramyltripeptide phosphatidylethanolamine

Mifamurtide is a conjugate of muramyl tripeptide linked to dipalmitoyl phosphatidyl ethanolamine; the phospholipid facilitates incorporation of the peptide into liposomes. The agent stimulates macrophages to seek out and destroy cancer cells. The compound was originated by Novartis (formerly CIBA-Geigy), and is being developed by IDM Pharma for osteosarcoma. Mifamurtide is being reviewed by regulatory authorities in the US and EU for this indication.CIBA-Geigy originally developed mifamurtide in the early 1980s and the agent was subsequently outlicensed to Jenner Biotherapies in the 1990s. IDM Pharma acquired the rights to the drug from Jenner in April 2003.IDM and Genesis Pharma have entered into an exclusive licensing and marketing agreement for mifamurtide in South East Europe. Under the agreement terms, IDM will receive an upfront fee from Genesis, as well as milestone payments on reaching certain sales levels in the territory. Medison Pharma signed an agreement with IDM Pharma for the sales and marketing of mifamurtide in Israel. IDM will receive an upfront license fee from Medison and will be entitled to receive a milestone payment upon regulatory approval of the agent in Israel, as well as royalties on net sales.IDM outlicensed exclusive marketing rights for mifamurtide in the UK and Ireland to Cambridge Laboratories in June 2005. In exchange, IDM is entitled to an upfront license fee and milestone payments prior to launch, as well as royalties calculated on product sales.Previously, Chiron Vaccines (a joint venture between Novartis and Chiron formed in 1995) investigated mifamurtide as an adjuvant in HIV gp120 vaccine; however, development has been discontinued.IDM Pharma will purchase approximately 7.1 million shares of its common stock to raise approximately $US23.5 million in net proceeds. The company intends to use the funds for working capital and corporate purposes, including the company's activities related to gaining marketing approval of mifamurtide in the US and Europe. Following the announcement by ODAC in May 2007, IDM Pharma decided to amend the NDA for mifamurtide with additional vital status data from the completed phase III trial. This data was not available at the time the original filing was made, and the company believes that capturing this supplemental data will overcome the need for additional trials, further confirm the overall survival benefit of mifamurtide in osteosarcoma, and provide evidence for approvability. IDM Pharma intends to analyse the additional follow-up data and submit an amendment to the agency by the first quarter of 2008; the company is also working on addressing other concerns raised by the US FDA in the non-approvable letter. The US regulatory submission included safety and efficacy data from NCI-funded phase III trials in 678 patients with osteosarcoma conducted by the Pediatric Oncology Group and the Children's Cancer Group in over 147 US centres. The NDA also included safety and biological effects data of mifamurtide from 17 phase I and II studies in 248 patients conducted by Ciba-Geigy. In the EU, IDM Pharma filed a MAA with the EMEA in November 2006 for approval of mifamurtide (Mepacttrade mark) in combination with postoperative chemotherapy for the treatment of patients with newly diagnosed osteosarcoma following complete surgical resection. The company expects that the EMEA will make a decision regarding marketing approval for mifamurtide by the end of 2007. Mifamurtide has orphan drug status for the treatment of osteosarcoma in the US and EU.     

Methods to Account for Inaccuracies in the Dosing History When Performing Population Pharmacokinetic Analysis

Purpose  To develop and assess methods to account for missing dose history (MDH). Methods  A simulation study was performed with different doses, dose times and formulations using NONMEM. Four methods were used to account for MDH, these were the ideal dose method (IDM) which uses the actual dose history, the concentration minimum method (CMM) which assumes that the nominal dose history is accurate, the extrapolation subtraction method (ESM) which estimates the residual concentration at the time of the study dose and the concentration time method (CTM) where the time of the previous dose event is estimated. The CTM is a new method. Results  The CTM was superior to ESM and CMM and provided parameter estimates that were comparable in accuracy to the IDM. Conclusions  When the nominal dosing history is available then the CTM is a simple and effective method to account for potential inaccuracies in the dose history.     

Gastrin-releasing peptide receptor antagonist or N-acetylcysteine combined with omeprazol protect against mitochondrial complex II inhibition in a rat model of gastritis

The pathophysiology of gastritis involves an imbalance between gastric acid attack and mucosal defence. In addition, the gastric mucosal injury results in adenosine triphosphate (ATP) depletion leading to mitochondrial dysfunction. Several studies have shown the association of mitochondrial disorders with gastrointestinal dysfunction. In the present study, we investigated the activity of mitochondrial respiratory chain complexes activity in the stomach of rats with gastritis induced by indomethacin (IDM) and treated with omeprazole (OM), N-acetylcysteine (NAC) and the gastrin-releasing peptide receptor (GRPR) antagonist RC-3095. Adult male Wistar rats were pre-treated for 7 days with OM, NAC, RC-3095, combination of OM plus RC-3095, OM plus NAC and water (control). The animals were then submitted to fasting for 24 hr; IDM was administered. The rats were killed 6 hr later, and the stomachs were used for evaluation of macroscopic damage and respiratory chain activity. Our results showed that complex I and IV activities were not affected by administration of IDM. On the other hand, complex II and III activities were inhibited. In addition, OM plus RC-3095 and OM plus NAC did not reverse complex II activity inhibition. However, the complex III activity inhibition was reversed only with the combined use of OM plus RC-3095 and OM plus NAC. Our results are in agreement with previous studies indicating mitochondrial dysfunction in the pathophysiology of gastrointestinal tract disease and we suggest that GRPR antagonism might be a novel therapeutic strategy in gastritis.